Existing real-time lidar systems consist of two general types. The first type consists of large and expensive mechanically scanned lidar systems such as the Velodyne-64, marketed by Velodyne Lidar, Inc. Such mechanically scanned lidar systems use large rotating mirrors to scan multiple laser beams and use time of flight detection of reflected laser pulses to measure the range of each spot along the beam directions. The second type consists of flash lidars that illuminate the entire scene with each pulse and use an array of time-gated photodiodes to image the reflected light and measure the range for each pixel.
Rotating mirror LIDAR systems are large, heavy, power-hungry, and have poor angular resolution in the elevation direction, which is limited by the number of laser beams, for example, 64 beams in the case of the Velodyne-64 lidar. The azimuth resolution is limited by the laser spot size. Flash lidar systems have limited range because the laser pulse power is spread out over the entire scene, which greatly reduces the amount of power reflected by an object and captured by the detector aperture. In addition, the flash lidar angular resolution and field of view are limited by the number of time-gated photodiodes in the detector array.
What is needed is a lidar with reduced size weight and power (SWAP) that has an improved field of view (FOV), range resolution, and angular resolution. Also needed is a lidar that enables imaging different parts of the 3D scene with variable resolution, thereby allowing high angular resolution 3D imaging of the most salient or important regions of interest while maintaining a high frame rate and keeping the computational load low. The embodiments of the present disclosure answer these and other needs.